This invention relates in general to the field of fluid pumping systems and, more particularly, to a fluid controlled pumping system and method.
Pumping units are used in a variety of applications for compressing, raising, or transferring fluids. For example, pumping units may be used in municipal water and sewage service applications, mining and/or hydrocarbon exploration and production applications, hydraulic motor applications, and consumer product manufacturing applications. Pumping units, such as progressive cavity pumps, centrifugal pumps, and other types of pumping devices, are generally disposed within a fluid and are used to compress or increase the pressure of the fluid, raise the fluid between different elevations, or transfer the fluid between various destinations.
Conventional pumping units, however, suffer several disadvantages. For example, conventional pumping units generally require some form of lubrication to remain operational. For instance, a progressive cavity pump generally includes a rotor disposed within a rubber stator. In operation, a rotational force is imparted to the rotor, thereby producing a corkscrew-like effect between the rotor and the stator to lift the fluid from one elevation to another. In the case of the progressive cavity pump, friction caused by the rotation of the rotor relative to the stator without fluid lubrication oftentimes causes the progressive cavity pump to fail within a relatively short period of time. Generally, the fluid that is being pumped provides the required lubrication. However, variations in the fluid level proximate to an inlet of the pumping unit may result in an absence of fluid lubrication for the pumping unit.
Thus, maintaining adequate fluid lubrication at the pumping unit is critical for the performance and longevity of pumping operations. Additionally, in centrifugal pumping applications, an absence of the fluid to be pumped may cause cavitation.
Accordingly, a need has arisen for an improved pumping system that provides increased control of fluid lubrication of the pumping unit. The present invention provides a fluid controlled pumping system and method that addresses shortcomings of prior pumping systems and methods.
According to one embodiment of the present invention, a fluid controlled pumping system includes a pumping unit disposed within a fluid cavity. The pumping unit includes a passage extending to a head of the pumping unit. The system also includes a pressure source coupled to the passage and operable to force a fluid outwardly from the head of the pumping unit through the passage. The system also includes a pressure sensor coupled to the passage and operable to determine a fluid pressure within the passage. The system further includes a controller coupled to the pumping unit and operable to regulate an operating parameter of the pumping unit in response to the fluid pressure.
According to another embodiment of the present invention, a method for fluid controlled pumping includes providing a pumping unit disposed within a fluid cavity. The pumping unit includes a passage extending to a head of the pumping unit. The method also includes forcing a fluid outwardly from the head of the pumping unit through the passage and determining a fluid pressure within the passage. The method also includes automatically regulating an operating parameter of the pumping unit in response to the fluid pressure.
The invention provides several technical advantages. For example, in one embodiment of the present invention, the system monitors the fluid pressure within the fluid cavity which corresponds to a level of the fluid within the fluid cavity. Based on the fluid pressure, the system controls the operating parameters of the pumping unit to ensure proper fluid lubrication during operation. Thus, as the fluid level decreases within the fluid cavity, the operating parameters of the pumping unit may be modified. For example, in response to a decrease in the fluid level within the fluid cavity, the operating speed of the pumping unit may also be decreased, thereby maintaining a substantially constant fluid level within the fluid cavity to provide required pumping unit lubrication. Additionally, operation of the pumping unit may also be ceased based on the fluid level within the fluid cavity to substantially prevent operation of the pumping unit absent fluid lubrication.
Another technical advantage of the present invention includes providing a flushing mechanism for substantially preventing a build-up of materials at the inlet of the pumping unit. For example, a progressive cavity pump may include an internal passage extending downwardly within a rotor of the pump and having an outlet disposed proximate to the inlet of the pump. A fluid may be provided downwardly within the passage and outwardly from the outlet of the passage to flush material accumulation build-up from the inlet of the pump and maintain material suspension within the pumped fluid if desired.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims.